Apparatus for rectifying alternating currents



Feb. 16, M32. D. G. ACKERLY APPARATUS FOR RECTIFYING ALTERNATINGCURRENTS Filed Feb. 19, 1931 INVENTOR. D. G linker/y, @R'W Fig: 2.

1 ATTORNEY.

Patented Feb. 16, 1932 UNITED STATES PATENT OFFICE DONALD G. AGKERLY, orEDGEWOOD, PENNSYLVANIA, AssIeNoR 'ro THE UNION SWITCH &SIG1\TAL COMPANY,OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA .errumrrus FORanc'rmYING ALTERNATING cmmms Application filed February 19, 1931. SerialNo. 516,996.

- My invention relates to apparatus for rectifying alternating current,and particularly to rectifying apparatus of the type comprisingasymmetric units, each conslsting of a metal member having a layer of acompound otherwise be possible.

I will describe one form of apparatus embodying my invention, and willthen point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a top plan view of rectifyingapparatus em-,

bodying my invention. Fig. 2 is an enlarged sectional view taken on theline IIII of Fig. 1.

Referring to the drawings, the rectifying apparatus in the form hereshown comprises 1 a plurality of similar full wave rectifiers, eachdesignated in its entirety by the reference character 1, andeachconsisting of a stack of asymmetric units 2. These asymmetric units maybe of any suitable type, and as here shown, each comprises a fiat disc 3of metal, such as copper, having a coating 4 of a compound of the metal,such as cuprous oxide formed thereon. Asymmetric units of the typedescribed exhibit the characteristic of offering a higherresistance tocurrent which tends to flow from the copper to the oxide. than tocurrent tending to flow in the opposite direction through the unit. Theunits of each rectifier are assembled on a suitable rod or bolt 5, whichpasses through suitable openings in the units, and which is insulatedfrom the units by a sleeve 6 of suitable insulating material such asfiber. Adjacent the coating 4 of cuprous oxide of each unit is placed athin layer 7 of an impressionable electrical. conducting material, suchas lead foil, and

interposed at suitable intervals in each rectifier are fins 8. thediameter of which isconslderably larger than the diameter of the units2. Each fin 8 is made up of some material which readily conducts heat,such for example, as copper.

Each rectifier is divided into four sections 9, 10 11 and 12respectively, each of which sections constitutes one leg of therectifier. As here shown, each section comprises six units in series,the units of each of the sec= tions 9 and 10 being assembled with thecoated side down, so that these sections will offer the lowestresistance to current tending to flow upwardly through the sections, andthe units of each of the sections 11 and 12 being assembled with thecoatedside up, so that these sections will offer the lowest resistanceto current tending to flow downwardly through the sections. It should beunderstood, however, that this particular arrangement is chosen merelyfor. convenience in illustrating my invention, and not by way oflimitation, the number and arrangement of washers in each section beingdetermined by the manner in which the rectifier is to be utilized.

As shown in the drawings, the rectifiers are arranged in concentriccircular rows and are connected together both electrically andmechanically by means of annular plates 13 which are perforated to fitover the bolts 5 and tubing 6. These plates also serve as baffles todirect the flow of air past the rectifiers as will be explainedhereinafter. The

plates 13 are assembled onto the bolts whilethe units are being stacked,and any desired number may be employed. As here shown, a plate 13 islocated at each end of the rectifiers, and at the junctions of thesections, thus providing a convenient means for electrically connectingthe corresponding sections of all of the rectifiers in multiple.

The rectifier stacks are each clamped together by means of nuts 14 and15, which are screwed onto the upper and lower ends, respectively, ofthe bolts 5. An insulating washer 16 is interposed between each nut andthe adjacentplate 13 to insulate the bolts from the plate. A saucershaped spring washer 17 is also interposed between each of the nuts 14or 15 and the associated insu. lating washer. 16 to maintain a uniformpressure on the stacks when the nuts are tightene'd. It will be notedthat the nuts 15 are provided with integral legs, thus permitting a freecirculation 0 air under the apparatus.

A vertical shaft 18 is rotatably mounted at the center of the. as aratusin suitable bearings 30, 3O supporte two of the stacks as illustrated inFig. 1, an fixed to the shaft are two fan blades 19 and 20 which arelocated in the openings in the upper and lower plates 13, respectively.These blades are so arranged that when the shaft 18 is rotated air willbe drawn in past all the rectifiersin directions which are controlled bythe baflie plates 13, and forced outwardly through the openings in theupper and lower lates, as indicated by the arrows. The sha 18 may berotated in any suitable manner. As here shown, it is connected with anelectric motor 21.

Th'e'electrical connections to the apparatus may be made by means ofterminals 29 which are fastened to the large annular discs 13.- Atransformer 22 is shown with its secondary 23 connected with thealternating current terminals of the a paratus, and a pair'ofwires 25and 26 are s own connected to thedirect current terminals. The polarityof the wires 25 and 26 is indicated by the plus and minus signs.Alternating current may be supplied to the primary 27 of transformer 22from any suitable source not shown in the drawings.

The operation of the apparatus as a whole is as follows: When motor 21is energized, the shaft 18 is rotated, and air is then drawn inwardlypast all of the units, by the fans 19 and 20, and is forced outwardlythrough the openings in the upper and lower units, as describedhereinbefore, the direction of the air flow being controlled by thebaflie plates 13. The air drawn in from the outside will have a highertemperature when it passes the inner circle of rectifiers than it had inpassing the outer circle, but since the area of the air passages betweenthe rectifiers of the inner circle is smaller, the velocity ofthe airwill be higher, so that more air will come in contact with the radiatingsurfaces. It will be apparent, therefore, that substantially uniformcooling of all of the reotifiers will take place. Due to the largeradiating surfaces provided by the bafiie plate and by the fins, theheat will be conducted away from the units at a very rapid rate, and itfollows that with rectifying apparatus constructed in accordance with myinvention, the units may be operated at very high current densities.

Although I have herein shown and described only one form of rectifyingapparatus embodying my invention, it is understood that various changesand modifications may be made therein within the $00 e of the a pendedclaims without departing from e spirit and scope of m invention.

Having thus descri ed my invention, what I claim is:

1. Apparatus for rectifying alternating currents comprising a pluralityof stacks of asymmetric units, a plurality of bafile plateseachassem'bled into all of said stacks in such manner that all of saidstacks are connected together "by said plates, said plates beingprovided with aligned apertures about which said stacks are arranged,and means for drawing air inwardly past all of said stacks and forcingit outwardly through certain ones of said apertures in such manner thatsubstantially uniform cooling at a rapid rate of all parts of all ofsaid stacks is effected.

2. Apparatus forrectifying. alternating currents comprising a pluralityof stacks of asymmetric units, a plurality of baffle plates eachassembled into all of said stacks in such manner that all of said stacksare connected together both electrically and mechanically by saidplates, said plates being provided with aligned apertures about whichsaid stacks are arranged, and means for drawing air inwardly past all ofsaid stacks and forcing it outwardly through certain ones of saidapertures in such manner that substantially uniform cooling at a rapidrate of all parts of all of said stacks is effected.

3. Apparatus for rectifying alternating currents comprising a pluralityof stacks of asymmetric units, a plurality of annular baffle plates eachassembled'into all of said stacks in such manner that said stacks areconnected together both electrically and mechanically by said plates,said stacks being arranged in circular rows about the openings in saidannular baflie plates, and means.

for drawin air inwardly past all of said stacks and forcing it outwardlythrough the apertures in the two end baflie plates, the spacing betweensaid stacks being such that the velocity of the air is higher when itpasses the inner stacks than it is when it passes the outer stacks.

4. Apparatus for rectifying alternating currents comprising a pluralityof stacks of asymmetric units, a plurality of annular baffle plates eachassembled into all of said stacks in such manner that said stacks areconnected together both electrically and mechanically by saidplates,said stacks being arranged in circular rows about the openings in saidannular bafile' plates, and two fans one located in the aperture in eachof the two end baflie plates, said fans being so arranged that when saidfans are operated air is drawn inwardly from all sides of the apparatusand is forced outwardly through the apertures in which said fans arelocated.

5. Apparatus for rectifying alternating currents comprising a pluralityof stacks of asymmetric units, a plurality of baflie plates eachassembled into all of said stacks in such manner that said stacks areconnected together both electrically and mechanically b said plates,said plates bein" provided wit aligned apertures, a rotatable shaftextending through said apertures, a pair of fan blades fixed to saidshaft and located in the apertures in the upper and lower plates,respectively, said blades being so arranged that when said shaft isrotated air is drawn inwardly past said stacks and is forced outwardlythrough the apertures in which said fan blades are located, and meansfor rotating said shaft.

6. Apparatus for rectifying alternating currents comprising a pluralityof stacks of asymmetric units, said stacks bein arranged in concentriccircular rows a p urality of annular bafile plates assembled into all ofsaid stacks, a rotatable shaft extending through the openings in saidannular plates, two fan blades attached to said shaft and one located inthe opening in each of the two end plates, said fan blades beingarranged toforce air outwardly through the associated opening, and meansfor rotating said shaft.

In testimony whereof I afiix my si ature.

DONALD G. AOKE LY.

